The present invention relates to an inclination sensor for detecting inclination of a vehicle, industrial machinery, and the like.
Inclination sensors of the kind, such as those shown in FIG. 45A and FIG. 45B and FIG. 46A and FIG. 46B have been suggested in the past. The inclination sensor shown in FIG. 45A and FIG. 45B confines an amount of mercury 202 within a hermetically sealed container 201. Terminals 203 and 204 are provided with one end of each protruding in the sealed container. When the inclination sensor is in a level position, the mercury 202 is situated as shown in FIG. 45A so that the terminals remain in an open state. If the inclination sensor tilts, the mercury 202 moves as shown in FIG. 45B into contact with the terminals 203 and 204 so that the two terminals turn into a state of conduction.
An inclination sensor shown in FIG. 46A and FIG. 46B, in which a magnet 212 and magnetic fluid 213 are confined in a hermetically sealed container 211, can detect an inclination by means of switching operation of contacts of a reed switch 214 provided beneath the container due to a variation of magnetic force, since the magnet 212 floating within the container 211 moves with an inclination of the container.
FIG. 46A and FIG. 46B depict the hermetically sealed container 211, the magnet 212, the magnetic fluid 213 and the reed switch 214. The magnet 212 and the magnetic fluid 213 confined in the hermetically sealed container 211 are freely movable within the hermetically sealed container 211. When the hermetically sealed container 211 is at a level, the magnet 212 and the magnetic fluid 213 are in the position as shown in FIG. 46A, so that contacts of the reed switch 214 are in their open state. If, however, the hermetically sealed container 211 tilts, the relative position between the magnet 212 in the hermetically sealed container 211 and the reed switch 214 changes, because the magnet 212 and the magnetic fluid 213 tend to maintain their position in a direction of gravity, as shown in FIG. 46B. This causes the magnet 212 to get closer to the contacts of the reed switch 214, so as to turn the contacts into a state of conduction (i.e., closed), and the inclination is perceived.
The inclination sensors that use mercury 202 are not suitable for mass production, because they require careful handling and secure facilities in production.
Also, with inclination sensors that use magnetic fluid 213, it is not only difficult to maintain the property of the magnetic fluid 213 stable for a long time, but also such sensors have a shortcoming in that the liquidity decreases at low temperature, thereby exacerbating movements of the magnet 212. This raises the problem of reduced accuracy of detecting inclination.
Moreover, these sensors have yet another problem of producing erroneous signals, as the mercury and the magnetic fluid are liable to splash due to external disturbances, such as vibration and an impact, which tend to short-circuit the contacts.
The present invention is intended to solve the above problems, and it aims at providing an inclination sensor that is superior in rotational performance and long term stability, and is high in detecting accuracy, resistant to external disturbances and reliable.
In order to solve the above problems, the inclination sensor of the present invention comprises divided frames provided within a fixation body to be fixed to a mounting body, a pendulum mounted rotatably to the divided frames, a magnetic flux generation means mounted on the pendulum, a reed switch mounted on a part of the divided frames in a manner to correspond with a rotational path of the magnetic flux generation means, and a damping body having nonmagnetic and electrically good conductive properties positioned on the divided frames along the rotational path of the magnetic flux generation means. The above structure can realize an inclination sensor that is superior in rotational performance and long term stability, and is high in detecting accuracy, resistant to external disturbances and reliable.